German patent document DE 10 2005 048 345 A1 discusses a handheld power tool auxiliary unit, which is configured as a replaceable tool attachment, including a percussion mechanism unit and a coupling unit, which is provided for coupling the percussion mechanism unit to a handheld power tool having a correspondingly configured interface. The percussion mechanism unit has a rotary percussion mechanism and is connectable to an associated insert tool. During operation of the tool attachment, which is coupled to a handheld power tool, the insert tool carries out a combined rotational and percussion movement when the rotary percussion mechanism is activated.